Aust prisoner in four-week hunger strike

Australian Jock Palfreeman's family fears he is at risk of starvation as his hunger strike over his treatment in a Bulgarian prison approaches 30 days.

Palfreeman, 32, is 11 years into a 20-year sentence for fatally stabbing Bulgarian law student Andrei Monov, 23, during a brawl in the capital Sofia in 2009.

The Sydneysider stopped eating on April 21 to protest the unfair treatment he claims to have suffered for his role in the Bulgarian Prisoners' Rehabilitation Association, the country's first prisoner rights and advocacy group, which he founded in 2013.

His father Simon Palfreeman has not been allowed to visit his son since he began his fast almost a month ago.

"My fear is that the time is now approaching when starvation could cause permanent damage," Dr Palfreeman told the ABC on Thursday.

Palfreeman's lawyer Kalin Angelov said in a post to supporters that Bulgarian authorities have been cracking down on the Australian for exposing corruption in the prison system and the abuse of inmates.

Mr Angelov said the Australian has been a model inmate with a completely clean record, until a new national government was elected in May 2017.

The incoming administration then began to wind back all Palfreeman's privileges, his lawyer said.

Palfreeman launched his parole bid in May 2018, but Mr Angelov claims the authorities responded by punishing his client over a series of minor and untested allegations.

Mr Angelov said his client had been sacked from his prison job and denied access to phone cards to contact the outside world.

At one point, his lawyer claimed, Palfreeman was also moved from a low-security facility to the Sofia Prison hospital's infectious disease unit, where he was kept with tuberculosis patients in attempt at "deliberate infection".

Mr Angelov said the 32-year-old is challenging all his punishments in the courts, but sadly felt it necessary to withdraw his parole bid.

"Regardless of the potential for positive outcomes from his lawsuits, an excuse can always be found for him to be punished again and again," Mr Angelov wrote.

"He learned the harsh truth that whatever his behaviour in prison is, he would be kept in a situation of the permanently 'guilty of something' prisoner during the remaining years of his sentence."